Atom Optics: Using Light to Position Atoms

Abstract

In most conventional lithography techniques, a light-sensitive resist is used to transfer a pattern from a mask to a substrate. The process is massively parallel because one mask can be used to expose millions of features at the same time. The minimum size of the features that can be created with conventional lithography is of the order of half the wavelength of the light being used. Extensions of optical lithographic techniques, involving deep ultraviolet light, are predicted to reach a limit of approximately 0.10 μm[l] by the year 2001. Other exposure technologies such as electron beam and x-ray, that have been proposed for producing smaller features than ultraviolet light, are problematic. For example, in conventional electron beam systems the writing process is serial, so large complicated patterns take a very long time to write. Moreover, in both electron beam and x-ray lithography, the masks and the substrates can be damaged by the high energy beams. Thus, there is great interest in developing parallel techniques for creating nanometer-scale features without damage and without masks. The new field of atom optics offers various massively parallel fabrication techniques which hold the promise for creating nanometer-scale features with good contrast and high resolution using low energy atomic beams. These advantages are augmented by the “direct-write” nature of atom optical fabrication, that is, structures can be deposited directly on a substrate without the intermediate process steps involved with using a resist.